766 passing into Russia at 55, thence continuing across the middle of Siberia, north of China to Japan; thence south to the *iji Islands, to New Zealand, and North Australia; thence again to Mauritius and over all Africa to Madeira. But Koppen remarks that the southern distribution is uncertain and obscure. Taking exceptional distribution, it is well known that it occasionally appears in the British Isles, and has in them apparently been noticed as far north as Edinburgh; so also does it occasionally appear m Scandinavia, and it has probably been seen up to 63 N. in Fin land. Looking at this vast area, it is easy to conceive that an element of uncertainty must always exist with regard to the exact determination of the species, and in Europe especially is this the case, because (as before stated) there exists an apparently distinct species, known as P. cinerascens, which Koppen does not take into FIG. 1. Pachytylus migratorius. This and the other figures are all natural size. account. This latter species is certainly the most common of the "locusts" occasionally found in the British Isles, and De Selys- Longchamps is of opinion that it breeds regularly in Belgium, where as the true P. migratorius is only accidental in that country. In the case of this, as of all other locusts, it is impossible within the limits of this article to chronicle even the years of greatest abund ance. That they are probably as destructive now as formerly appears within the bounds of belief. At any rate we read that only a year or two ago a detachment of Russian soldiers in Turcomauia was so beset that a stampede at last took place, and eventually the men were held prisoners by the insects forty-eight hours until the villagers killed them and carried them away for manure, locomotion being as difficult as if the men had been on ice. Acrydium pereyrinum (fig. 2) can scarcely be considered even an accidental visitor to Europe ; yet it has been seen in the south of Spain, and, most extraordinarily, in many examples spread over a large part of England in the year 1869. It is a larger insect than P. migratorius. No serious attempt to define the range of this species ha 3 yet been made, but there is every reason to believe that it is the most destructive locust throughout Africa and India and other pans of tropical Asia, and its ravages are not one whit less important than are those of P. migratorius. Presumably it is the species that, on more than one occasion, has been noticed in a vast swarm in the Atlantic, very far from land, and presumably also it occurs in the West Indies and some parts of Central America. But it has been already remarked that A. americanum of North America, although so closely allied as to be scarcely distinguish able, is said not to be migratory, and is therefore scarcely a true " locust." In the Argentine Republic a (possibly) distinct species (A. paranense) is the migratory locust. Caloptenus italicus (fig. 3) is a smaller insect, with a less extended area of migration ; and, though from this cause its ravages are not so notable,still the destruction occasioned in the districts to which FIG. 2. Acrydium peregrinum. it is limited is often scarce less than that of its more terrible allies. It is essentially a species of the Mediterranean district, and especially of the European side of that sea, yet it is also found in North Africa, and appears to extend far into southern Russia. FIG. 3. Caloptenus italicus. Caloptenus sfirctus (fig. 4) is the " Rocky Mountain locust" or hateful grasshopper " of the North American continent. Though a comparatively small insect, not so large as some of the grass hoppers of English fields, its destructiveness has procured for it within the last twenty years a notoriety scarcely excelled by that of any other. It is only recently that the persistent migration of American settlers westward extended into the home of this creature. Travellers and prospectors in these regions had previously spoken of enormous swarms of a destructive grasshopper as existing there, and no doubt these occasionally extended into regions already civilized, but the species was not recognized as distinct from some of its non-migratory congeners to which it is so closely allied as to require a practised entomological eye to separate it therefrom. As time drew on, the various "State entomologists" made it their special duty to report on the insect, and at length, in 1877, _the matter had become so serious that Congress appointed a United
